#!/usr/bin/env python
#
# Copyright 2012-2013 Ettus Research LLC
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

import atexit
import hashlib
from optparse import OptionParser
import os
import os.path
import shutil
import string
import sys
import tempfile
import urllib2
import zipfile

def md5Checksum(filePath):
    with open(filePath, 'rb') as fh:
        m = hashlib.md5()
        while True:
            data = fh.read(8192)
            if not data:
                break
            m.update(data)
        return m.hexdigest()

class temp_dir():

    def __enter__(self):
        self.name = tempfile.mkdtemp()
        return self.name
    def __exit__(self, type, value, traceback):
        try:
            shutil.rmtree(self.name)
        except OSError:
            #Utility should have already detected this, but this is for safety
            raise Exception("Could not install images! Make sure you have write permissions.")

if __name__ == "__main__":

    print
    if os.environ.get("UHD_IMAGES_DIR") != None and os.environ.get("UHD_IMAGES_DIR") != "":
        default_images_dir = os.environ.get("UHD_IMAGES_DIR")
        print "UHD_IMAGES_DIR environment variable is set. Default install location: %s" % default_images_dir
    else:
        default_images_dir = "@CMAKE_INSTALL_PREFIX@/share/uhd/images"

    #Command line options
    parser = OptionParser()
    parser.add_option("--install-location", type="string", default=default_images_dir, help="Set custom install location for images")
    parser.add_option("--buffer-size", type="int", default=8192, help="Set download buffer size, [default=%default]",)
    (options, args) = parser.parse_args()
    
    #Configuring image download info
    images_src = "@UHD_IMAGES_DOWNLOAD_SRC@"
    images_zip_md5sum = "@UHD_IMAGES_MD5SUM@"
    filename = images_src.split("/")[-1]

    #Use this directory with relative paths
    current_directory = os.getcwd()

    with temp_dir() as dirname:
        os.chdir(dirname)

        if options.install_location == default_images_dir:
            images_dir = default_images_dir
        elif os.path.isabs(options.install_location):
            #Custom absolute path given
            images_dir = options.install_location
        else:
            #Custom relative path given, so construct absolute path
            images_dir = os.path.abspath(os.path.join(current_directory, options.install_location))

        #Before doing anything, check for write permissions in parent directory
        parent_directory = os.path.dirname(images_dir)
        if os.access(parent_directory, os.W_OK):
            print "Downloading images to: %s" % images_dir
        else:
            print "You do not have write permissions at the install location!"
            sys.exit(1)

        opener = urllib2.build_opener()
        opener.add_headers = [('User-Agent', 'UHD Images Downloader')]
        u = opener.open(images_src)
        f = open(filename, "wb")
        meta = u.info()
        filesize = float(meta.getheaders("Content-Length")[0])
        
        print "Downloading images from: %s" % images_src
        
        filesize_dl = 0.0

        #Downloading file    
        while True:
            buffer = u.read(options.buffer_size)
            if not buffer:
                break
        
            filesize_dl -= len(buffer)
            f.write(buffer)

            status = r"%2.2f MB/%2.2f MB (%3.2f" % (-filesize_dl/1e6, filesize/1e6, (-filesize_dl*100.)/filesize) + r"%)"
            status += chr(8)*(len(status)+1)
            print status,
        
        f.close()

        #Checking md5sum of zip file
        downloaded_zip_md5sum = md5Checksum(filename)
        if images_zip_md5sum != downloaded_zip_md5sum:
            print "\nMD5 checksum does not match!"
            print "Expected %s, got %s" % (images_zip_md5sum, downloaded_zip_md5sum)
            os.remove(filename)
            os.chdir("/".join(images_dir.split("/")[:-1]))
        else:
            #Extracting contents of zip file
            if os.path.exists("tempdir"):
                shutil.rmtree("tempdir")
            os.mkdir("tempdir")

            images_zip = zipfile.ZipFile(filename)
            images_zip.extractall("tempdir")

            #Removing images currently in images_dir
            if os.path.exists(images_dir):
                try:
                    shutil.rmtree(images_dir)
                except OSError:
                    print "Make sure you have write permissions in the images directory."
                    sys.exit(1)

            #Copying downloaded images into images_dir
            shutil.copytree(os.path.join('tempdir', os.path.splitext(filename)[0], 'share', 'uhd', 'images'), images_dir)

            #Removing tempdir and zip file
            shutil.rmtree("tempdir")
            images_zip.close()
            os.remove(filename)

            os.chdir(images_dir)
            print "\nImages successfully installed to: %s" % images_dir